General Description
The MAX6643/MAX6644/MAX6645 monitor temperature and automatically adjust fan speed to ensure optimum cooling while minimizing acoustic noise from the fan. Each device measures two temperature locations.

FEATUREs
♦ Simple, Automatic Fan-Speed Control
♦ Internal and External Temperature Sensing
♦ Detect Fan Failure Through Locked-Rotor Output, Tachometer Output, or Fan-Supply Current Sensing
♦ Multiple, 1.6% Output Duty-Cycle Steps for Low Audibility of Fan-Speed Changes
♦ Pin-Selectable or Factory-Selectable LowTemperature Fan Threshold
♦ Pin-Selectable or Factory-Selectable HighTemperature Fan Threshold
♦ Spin-Up Time Ensures Fan Start
♦ Fan-Start Delay Minimizes Power-Supply Load at Power-Up
♦ 32Hz PWM Output
♦ Controlled Duty-Cycle Rate-of-Change Ensures Good Acoustic Performance
♦ 2°C Temperature-Measurement Accuracy
♦ FULLSPD/FULLSPD Input Sets PWM to 100%
♦ Pin-Selectable OT Output Threshold
♦ 16-Pin QSOP and 10-Pin µMAX Packages

APPLICATIONs
   Networking Equipment
   Storage Equipment
   Servers
   Desktop Computers
   Workstations